‘While we still have time’: DuPage County ecologists working to save endangered dragonfly

Preserving a species is painstaking, time-consuming work.

Andres Ortega, aquatic resources supervisor with the Forest Preserve District of DuPage County, knows that firsthand.

For nearly a decade, Ortega and his colleagues at the District’s Urban Stream Research Center in Warrenville have worked to preserve the Hine’s emerald dragonfly, a rare and endangered species that inhabits the Des Plaines River valley.

Such efforts occasionally encounter resistance from people who question the necessity of preserving obscure, seemingly minor animals and plants.

But Ortega cautions against dismissing those efforts, noting the harm that can accompany the loss of a “keystone species,” on which the survival of other species and their ecosystems depend.

Throughout history, humans have “found out the hard way how important one species can be, and we generally only find that out after the species is gone,” Ortega said.

“The removal of one species can have catastrophic effects,” he added.

Ortega cited as an example the gray wolf, a keystone species that was nearly extinct by the mid-20th century. The absence of the apex predator in Yellowstone National Park resulted in an increased elk population whose overgrazing upset the natural balance, diminished other species and eroded riverbanks.

While he cannot say for certain that dragonflies function in the same way, the species is among the top invertebrate predators, responsible for controlling pests, mosquitoes and other flying insects among them.

Named for their emerald-colored eyes, Hine’s emerald dragonflies measure about 2⅟₂ inches, have a wingspan of 3⅟₂ inches and possess near 360-degree vision. Because they require a specialized habitat, the Hine’s emeralds likely have always been rare, said Ortega, who attributes the species' decline to habitat loss.

“Their decline and risk of extinction is due to human impact on their habitats,” he said. “If we have the ability to reverse some of the damage we’ve done, we have a moral obligation to do what we can to reverse that impact while we still have time.”

DuPage County’s preservation efforts commenced in 2016, after the U.S. Fish and Wildlife Service asked the district to participate in a captive rearing program in partnership with the University of South Dakota and the Illinois Department of Natural Resources. Over the years, other partners have included the Shedd Aquarium and the Lincoln Park and Brookfield zoos.

Every breeding season, University of South Dakota ecologists use noninvasive methods to capture female dragonflies in butterfly nets, after which they dip their abdomens in water to release their eggs.

Researchers then collect the eggs and distribute them to partner organizations, including the Urban Stream Research Center, which receives them in October.

The eggs are refrigerated until early spring, when Ortega and his colleagues check if they've hatched. If they have, the microscopic dragonflies or larvae are placed in a cup filled with sediment and fed tiny organisms three times a week for another two to three months.

At that point, they’re placed in larger tanks stocked with other prey, including tiny crustaceans and pill bugs. In the fall, researchers slowly cool the tanks to simulate fall and winter temperatures, sending the larvae into a kind of insect hibernation until the spring, when they slowly warm up the tanks.

The process of cooling and warming repeats for up to three years, during which the dragonflies remain in the larvae stage. Only then, during warm weather when they have the best chance of surviving, are the adults released into their habitat, where their life span of 3 to 6 weeks is long enough to mate, create the next generation and expire, according to Ortega.

“We want to make sure when they are ready to emerge as adults, they do so at the right time of the year,” he said. “We don't want them to emerge in December. If they do, they won't survive until spring.”

According to Ortega, the district's efforts typically produce 200 to 300 adult Hine’s emeralds annually.

Besides Illinois, the dragonflies exist in Wisconsin, Michigan and Missouri. Wisconsin’s population is the largest and most stable. Illinois’ is the smallest, but Ortega says it’s believed to be the most genetically diverse, a characteristic researchers want to preserve.

Despite the efforts of Ortega and his colleagues, the Hine’s emerald remains on the endangered list.

There are limitations to what individuals can do to help preserve them beyond protecting waterways by using chemicals responsibly, and incorporating native plants into their landscaping. Those plants attract native insects that serve as a dragonfly’s food source.

Ortega also encourages people to learn how endangered species benefit the ecosystem and share that information with others.

“In doing so you can become an advocate not just for Hine’s emerald, but for all endangered species,” he said.